package com.example.ailiyuncloud.beCurrent;

import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.LinkedBlockingQueue;
import java.util.concurrent.ThreadPoolExecutor;
import java.util.concurrent.TimeUnit;

public class ExecutorConfig {
    private static int maxPoolSize = Runtime.getRuntime().availableProcessors();
    private volatile static ExecutorService executorService;

    public static ExecutorService getThreadPool() {
        if (executorService == null) {
            synchronized (ExecutorConfig.class) {
                if (executorService == null) {
                    executorService = newThreadPool();
                }
            }
        }
        return executorService;
    }

    private static ExecutorService newThreadPool() {
        int queueSize = 500;
        int corePool = Math.min(5, maxPoolSize);
        return new ThreadPoolExecutor(corePool, maxPoolSize, 10000L, TimeUnit.MILLISECONDS,
                new LinkedBlockingQueue<>(queueSize), new ThreadPoolExecutor.AbortPolicy());
    }

    private ExecutorConfig() {
    }


    public static <T> List<List<T>> averageAssign(List<T> source, int n) {
        List<List<T>> result = new ArrayList<List<T>>();
        int remaider = source.size() % n;
        int number = source.size() / n;
        int offset = 0;//偏移量
        for (int i = 0; i < n; i++) {
            List<T> value = null;
            if (remaider > 0) {
                value = source.subList(i * number + offset, (i + 1) * number + offset + 1);
                remaider--;
                offset++;
            } else {
                value = source.subList(i * number + offset, (i + 1) * number + offset);
            }
            result.add(value);
        }
        return result;

    }
}
